Dental implement



Nov. 25, 1952 BERGENDAL 2,618,855

DENTAL IMPLEMENT Filed May 6, 1949 Patented Nov. 25, 1952 UNITED STATESPATENT DENTAL IMPLEMENT Gunnar Bergendal, Angby, near Stockholm,

Sweden Application May 6, 1949, Serial No. 91,786 In Sweden May 19, 19481 Claim. 1

This invention relates to dental implements, and particularly togrinding tools for use in preparing teeth for the application ofartificial crowns thereon.

One object of the invention is to provide such a tool which enables thedentist to perform the work referred to exactly and rapidly.

A further object of the invention is to provide such a tool which isself-guiding during use.

Another object of the invention is to provide such a tool whichautomatically prevents grinding beyond any desired limit.

Still another object of the invention is to provide such tool whichcannot hurt either the patients soft mouth parts or teeth adjacent tothe one undergoing work.

To the accomplishment of the foregoin and other objects the inventionconsists of the structure hereinafter described and pointed out in theappended claim, the annexed drawing and the following descriptionsetting forth in detail a structural embodiment, such disclosedstructure constituting on of the many forms in which the principles ofthe invention may be realized.

In said drawing:

Fig. 1 is a side elevation of an embodiment of the invention.

Fig. 2 is a left-hand .end view of the tool shown in Fig. 1.

Fig. 3 illustrates diagrammatically the use of the form of tool shown inFigs. 1 and 2, said tool and the tooth undergoing preparation being bothshown in side elevation.

Figs. 1 and 2 show a grinding disk I provided with a shaft 2 at rightangles to the plane of said disk and with an abrasive 3 at one end facethereof. The characteristic feature of this form of my invention is thatthe circumference of the grinding disk I and an annular zone internallythereof are not provided with abrasive for the purpose of forming a stopmember or feeler 4 rotating with the grinding disk I. As may be seenmore clearly from Fig. 2 the abrasive 3 is countersunk so as to besubstantially flush with the adjacent plane breast face 5 of the flange4 and besides the latter is rounded off as shown to avoid sharp edges.

Figs. 1 and 2 shows a cylindrical grinding wheel I provided with anabrasive 3 at its circumference and at one of its end faces whereas itsopposite end face is united to a smooth disk 4 the diameter of which issomewhat larger than that of the grinding wheel proper. As will appearfrom the following the smooth flange 5 of the disk 4 situated externallyand laterally of the grinding wheel I forms a stop member or guiderotating with the grinding wheel I so as to facilitate the shaping of ashoulder in preparing a tooth to b provided with a jacket crown. Thesmooth rigid disc is concentrically mounted on a spindle 2 shaft 2 andthe grinding wheel is also concentric with the smooth disc and saidshaft.

The advantages resulting from the use of my present improved dentalimplement will clearly appear from a study of Fig. 3.

In using the tool illustrated in Fig. 3 the dentist works his waydownwardly and inwardly by means of the grinding wheel i and then thesmooth guide flange '5 when entering the gums pocket, stops the toolwhereby the correct position of a shoulder l in vertical direction issecured. Simultaneously the guide 5 prevents the dentist from workinghis way too far into the teeth. With this guide or stop member omittedit might happen that the dentist even if he works very cautiously wouldgrind off the tooth too much both vertically and horizontally in shapingthe shoulder 1. Thus, the guide 5 forms a simple but efficient means forfacilitating the preparatory work referred to and permits the dentist towork more safely and rapidly in shaping the shoulder.

From the foregoing it may be seen that by my present invention I haveprovided a grinding tool for dental use which although of very simpledesign greatly facilitates the tooth preparation referred to and effectsso to speak a positive control of the tool by means of the smoothnongrinding stop member or guide rotating with the grinding tool proper.Nor will this smooth and noncutting member hurt any soft parts duringuse.

What I claim is:

A dental grinding tool for external work on teeth comprising a rigidcircular disc rotatable about an axis at right angles to the planethereof, said disc having a cylindrical disc of abrasive vmaterialpermanently coaXially secured to one .face thereof, and said disc ofabrasive material being of smaller diameter than the first mentioneddisc, the edge-portion of said first disc extending radially outwardlyfrom immediately adjacent the cylindrical abrasive disc and said edgeportion being smooth and continuous so as to serve in use as a guidewhich performs no abrading action.

GUNNAR. BERGENDAL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 774,612 Stead Nov. 8, 19041,809,907 Newcomb Jan. 16, 1931 2,453,696 1 Brooks Nov. 16, 1948

